Hybrid and Spanning External Fixation

1. Hybrid and Spanning External Fixation Wayne Cheng, MD Assistant Professor Department of Orthopaedic Surgery Loma Linda University Medical Center SEP 17, 2006

2. History • Jean-Francois Malgaigne, 1840 • Malgaigne’s point • Malgaigne’s claw • Clayton Parkhill, 1897 • Bone clamp • Lambotte • Lambotte ext fixator

3. 1940 to 1970 x

4. Hybrid External fixator • Soft tissue reaction • Affixing smaller metaphyseal fragm • Cancellous bone • Trampoline effect • Half pins

5. Biomechanics - stability S = r 4 • Wire diameter • Wire tension • Crossing angle • Distance ring to bone • # of wire • Olive wire • Center bone Optimal = 50% of yield strength (80 – 90 kg)

7. Location at proximal tibia Tornetta et al, JOT 2000

8. Knee capsular reflection • 14 MM • 10% Spence Reid, MD

9. Safe corridors distal tibia Vives JOT 15 (8) 2001

10. Ankle capsule Superior capsular reflection 21 mm from antmed joint line

11. Insertion technique

12. Case example 1

13. Case example 1 – post op

14. Case 2

15. Case example 2

16. Case 2 - final

17. Is hybrid any good? • 31 complex proxm tibia fx. • 3.7 year f/u • Functional grading (rasmussen) • 84% good • 12% fair • 3% poor • Complication • 23% pin tract infx. • 1 AKA

18. Why did hybrid fall out of favor? • High maintenance/malunion/nonunion • Cumbersome/bulky • Pin tract infection • Meticulous insertion/assembly • Fracture through pin sites • expensive

19. Spanning External fixation + secondary internal fixation

20. Spanning external fixation

21. Spanning external fixation

22. Conclusion • Spanning external fixation is a valuable tool for initial soft tissue management • 2nd stage internal fixation is attractive. • Hybrid external fixation is a tool that may be valuable in selected cases.

23. THANK Y0U